Yes, OLYMPIAD is a Scrabble word!

Letter values in Scrabble US: O 1, L 1, Y 4, M 3, P 3, I 1, A 1, D 2.

Is it a valid word?

OLYMPIAD is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

one of the four-year intervals between Olympic Games; used to reckon time in ancient Greece for twelve centuries beginning in 776 BC
the modern revival of the ancient games held once every 4 years in a selected country

Also: olympic games.

Not playable in Scrabble US: OLYMPICS.